We went from 159M down to 133M during the pandemic, and then recovered to around 150M by the time Trump was run out of office.
At that time in January of 2021, we had been stuck at the 150M mark for nearly 5 months.
Then Joe came in, got vaccine distribution online (which Trump had NO plan for even after OWS), and the economy started booming as it usually does when Democrats clean up after Republicans (see 1990s, 2010s, 2020s).
Between the huge number of small businesses that failed under Trump, and the loss of nearly a million Americans to his inept bungling of the pandemic, there was no guarantee those jobs would ever 'come back', because both the workers and the companies they worked for were gone.